body {
  height: 100vh;
  background: url(../img/gou.jpg) no-repeat center;
  background-size: cover;
}

.header-in {
  height: 80px;
  line-height: 80px;
  text-align: center;
  font-size: 22px;
  font-weight: 500;
  color: #fb7299;
}

.control-in {
  /* background-color: aqua; */
  text-align: center;
}

.control button {
  background-color: #fb7299;
  color: #fff;
  text-align: center;
  font-size: 16px;
  cursor: pointer;
  transition: background-color .3s;
  padding: 8px 20px;
  border-radius: 2px;

}

.control button:hover {
  background-color: #ed8ca8;
}

.stu-in {
  /* background-color: #ed8ca8; */
  /* height: 400px; */

}

.group h3 {
  height: 40px;
  line-height: 40px;
  text-align: center;
}

.group ul {
  display: flex;
  justify-content: center;
}


.group ul li {
  margin: 5px;
  width: 120px;
  height: 50px;
  line-height: 50px;
  box-sizing: content-box;
  border: 1px solid #f1f2f3;
  border-radius: 6px;
  background-color: #f6f7f8;
  color: #61666d;
  text-align: center;
  font-weight: 400;
  transition: background-color .3s, color .3s;
}

.group ul li.active {
  background-color: #438cd4;
  color: #fff;
}

.countdown {
  text-align: center;
}